Now the 63-year-old actor has turned his attention to a sweetly optimistic but past-his-prime TV writer named Uncle Saul for CBS’s new sitcom “Welcome to the Captain.” Set in a Hollywood apartment tower with a storied history – called El Capitan, and affectionately The Captain — and currently home to plenty of showbiz aspirants and has-beens, Uncle Saul is the eyes, ears and heart of the building.

“Uncle Saul believes in talent, in love, and in imagination,” says Tambor. “And like Hank, my character on ‘Larry Sanders,’ he has no idea that his time is over. Yet he takes the time to mentor this young man. That to me is what’s sad and wonderful and terrific about him.”

Saul has also had a fruitless crush on Charlene, The Captain’s aged starlet, played by a still-vivacious-looking Raquel Welch.

“He’s charming in his innocence,” says Tambor. “He’s been chasing her for 19 years, and I don’t think they’ve had a date. But he still thinks he’s closing.”

Tambor says the key to playing characters like Uncle Saul and Hank Kingsley – fueled by a perhaps unearned confidence in their abilities – is to avoid prejudging them.

“What you try to do in comedy is never wink,” he says. “I never thought Hank was a doofus. I just sort of believed in him. The secret is, you’ve got to like the guy. And I like Uncle Saul. He’s outdated and wonderful.”

There are some elements to this particular role and project that Tambor admits are kind of eerily close to his own life. Uncle Saul’s only real scripting credit was writing on “Three’s Company,” a show that Tambor himself had a recurring role on. Plus, says Tambor, “When I first came to Los Angeles as a young actor, I actually stayed in a little enclave off of Sunset like The Captain, with character actors and writers, from the famous to the infamous. And Mickey Ross, one of the creators of ‘Three’s Company,’ sort of mentored me the same way Saul does. When you get to my age, things just come around.”

He’d prefer people not assume the cluelessness of his characters is a Tambor trait as well, though. Let it be known, for instance, that he does not own the red “Three’s Company” jacket he sports in an upcoming episode of “Welcome to the Captain,” when Uncle Saul makes a tragic effort to seem hip at a disco. While shooting those scenes on location at a real club, Tambor wore the logo-emblazoned piece of cheeseball retro apparel when he went to lunch at the legendary Hollywood eatery Musso & Frank’s next door.

He suddenly realized the perils of an inside joke unveiled too early.

“People were smiling and waving and it didn’t hit me till I was halfway through the restaurant that these people probably think I’m Jeffrey Tambor wearing a ‘Three’s Company’ jacket,” he says, laughing. “Well, I hightailed it out. I told [“Welcome to the Captain” creator] John Hamburg I’ve never heard him laugh so hard.”

The San Francisco-born Tambor always knew, though, that he’d be a character actor. “I lost my hair when I was 17, so I started to go off to summer stock and I was playing old men right off the bat,” says Tambor, who eventually earned his masters in speech and theater at Wayne State University in Detroit. “I never really played my age until right about now.”

Tambor, whose career easily shifts between television, movies and the stage, recently got back from six months in Budapest, Hungary where he filmed the sequel to “Hellboy.” He took his wife Kasia and their two children Gabriel, 3, and Eve, 1. (He has an adult daughter Molly from a previous marriage.)

“We had a great time,” he says. “I had a bike and rode all around the city.” People recognized him, too, he assumes because of the “Arrested Development” DVD that had just come out. “People would come up and say things,” he says. “I couldn’t always understand what they were saying, but ‘George Senior’ was always in there and there was a smile on their faces. It seemed good!”